EP0612827A1 - Verfahren zur Herstellung von Verbundmaterialien auf Basis von Polymeren und Flüssigkristallen mit dichroitischen Farbstoffen - Google Patents

Verfahren zur Herstellung von Verbundmaterialien auf Basis von Polymeren und Flüssigkristallen mit dichroitischen Farbstoffen Download PDF

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Publication number
EP0612827A1
EP0612827A1 EP94400358A EP94400358A EP0612827A1 EP 0612827 A1 EP0612827 A1 EP 0612827A1 EP 94400358 A EP94400358 A EP 94400358A EP 94400358 A EP94400358 A EP 94400358A EP 0612827 A1 EP0612827 A1 EP 0612827A1
Authority
EP
European Patent Office
Prior art keywords
liquid crystal
display screen
polymer
solvent
composite material
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP94400358A
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English (en)
French (fr)
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EP0612827B1 (de
Inventor
Laurent Bouteiller
Pierre Le Barny
Jean-Pierre Vairon
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Thales SA
Original Assignee
Thomson CSF SA
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Publication date
Application filed by Thomson CSF SA filed Critical Thomson CSF SA
Publication of EP0612827A1 publication Critical patent/EP0612827A1/de
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Publication of EP0612827B1 publication Critical patent/EP0612827B1/de
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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K19/00—Liquid crystal materials
    • C09K19/52—Liquid crystal materials characterised by components which are not liquid crystals, e.g. additives with special physical aspect: solvents, solid particles
    • C09K19/54—Additives having no specific mesophase characterised by their chemical composition
    • C09K19/542—Macromolecular compounds
    • C09K19/544—Macromolecular compounds as dispersing or encapsulating medium around the liquid crystal
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1334—Constructional arrangements; Manufacturing methods based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals

Definitions

  • the field of the invention is that of display screens operating in particular in reflection. More precisely, this is the field of screens made from polymer-liquid crystal composites containing dichroic dyes.
  • a film of polymer-colored liquid crystal composite is between two transparent conductive electrodes.
  • the colored liquid crystal is obtained by dilution of coloring molecules between molecules of liquid crystal.
  • the film is diffusing due to the differences in index between polymer and liquid crystal, and more absorbent due to dye molecules whose orientation imposed by that of the liquid crystal varies randomly from one domain to another.
  • the liquid crystal molecules orient themselves with the dichroic chosen dye molecules, parallel to the applied electric field.
  • a transparent film is obtained under an electric field.
  • Such a film is therefore capable of offering two states, a diffusing and absorbing state and a non-absorbing transparent state.
  • the contrast obtained with such composites is much more satisfactory than that proposed with composites which do not contain dichroic dyes and which have only a diffusing state and a transparent state.
  • the porous film of crosslinked polymer can advantageously be obtained from a mixture (M) o of photopolymerizable monomer, photoinitiator and liquid crystal (XL).
  • the monomer is preferably polyfunctional so as to form a network during the polymerization.
  • the mixture (M) o can be introduced by capillary action into a removable cell comprising a substrate (S) and a second substrate (S) o of low surface energy, separated from the substrate (S) by shims.
  • the photopolymerization of the mixture (M) o can be carried out by irradiation of ultraviolet rays through the substrate (S) o .
  • the substrate (S) o can then advantageously be removed to wash the film of crosslinked polymer and comprising inclusions of liquid crystal (X) o .
  • This step is carried out using a solvent capable of swelling the polymer, thereby enabling the exclusion of the liquid crystal (XL) o , leaving a porous film of crosslinked polymer.
  • the porous film of crosslinked polymer can also be obtained from a mixture (M) ' o containing a monomer and a liquid solvent for the monomer, non-solvent for the polymer and of low surface tension at room temperature.
  • the polymerization can be initiated according to conventional methods, of polymerization.
  • PDLCs have the advantage of offering good mechanical strength, making the use of sealing joints unnecessary but nevertheless offering relatively high control voltages.
  • networks with a high rate of liquid crystal which have very low voltages may have poorer mechanical performance. This is why it is very advantageous to have an implementation method applicable in a wide range of liquid crystal concentrations to optimize the composite polymer / liquid crystal film.
  • This mixture (M) can advantageously be introduced by capillary action into a cell previously formed by a transparent conductive substrate (S) (it can be a strip of transparent material covered with a thin conductive layer of indium oxide and tin), a substrate (S) o of low surface energy (it may be Teflon) which can be easily separated from a polymer film, and shims of known and controlled thickness, all substrates (S) and (S) o and shims being held by clamps.
  • the cell thus prepared and filled can be irradiated by ultraviolet radiation as illustrated in FIG. 1.
  • a crosslinked polymer network is then obtained containing liquid crystal inclusions (XL) o , the volume of these inclusions being governed by the content in mixture (B) in mixture (M) o .
  • the cell can then be opened, the substrate (S) o adhering little to the previously formed film.
  • Said film can thus be washed with a solvent (L) o capable of swelling the polymer network and allowing the extraction of traces of monomers and initiator as well as the extraction of liquid crystal (XL).
  • a second mixture (M) comprising a solvent (L) also capable of swelling the polymer and possibly also being the solvent (L) o and a mixture of liquid crystal (XL) and dye (C) (the percentage of dye (C) being very weak compared to that of liquid crystal) is brought into contact with the porous film of crosslinked polymer so as to diffuse the liquid crystal (XL) and the dye (C) within the network formed.
  • the solvents (L) o and (L) can be dichloromethane or hexane.
  • the solvent is then allowed to evaporate (L), then the porous film of crosslinked polymer is dried under vacuum in order to remove the last traces of solvent.
  • a second conductive and transparent substrate (S) ′ is deposited on the polymer film containing inclusions of more coloring liquid crystal.
  • the screen thus produced has a much higher contrast than the identical screen containing no dye. Optimizing the polymer content of the dye and the thickness of the film makes it possible to obtain both good contrast and low control voltage.
  • the dichloromethane is allowed to evaporate for several hours. We prefer a sufficiently slow evaporation kinetics so as to introduce the maximum of liquid crystal and coloring entities within the pores of the network formed.
  • the film is then dried under vacuum for one hour. Finally, a second conductive substrate is applied.
  • the screen thus obtained is characterized by measuring the transmission as a function of the control voltage.
  • the transmission ratio Tmax / Tmin 1450, Tmax corresponding to the maximum transmission that can be reached under voltage and Tmin corresponding to the transmission of the diffusing state at rest without voltage applied to the screen.
  • FIG. 2 illustrates the evolution of the transmission of the screen as a function of the voltage applied to the screen produced according to the invention. It thus appears that the voltage necessary to obtain 90% of transmission is of the order of 47 V.

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  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Liquid Crystal (AREA)
EP94400358A 1993-02-23 1994-02-18 Verfahren zur Herstellung von Verbundmaterialien auf Basis von Polymeren und Flüssigkristallen mit dichroitischen Farbstoffen Expired - Lifetime EP0612827B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9302057A FR2702058B1 (fr) 1993-02-23 1993-02-23 Procédé d'obtention de matériaux composites à base de polymère et de cristaux liquides avec colorants dichroiques.
FR9302057 1993-02-23

Publications (2)

Publication Number Publication Date
EP0612827A1 true EP0612827A1 (de) 1994-08-31
EP0612827B1 EP0612827B1 (de) 1998-11-25

Family

ID=9444336

Family Applications (1)

Application Number Title Priority Date Filing Date
EP94400358A Expired - Lifetime EP0612827B1 (de) 1993-02-23 1994-02-18 Verfahren zur Herstellung von Verbundmaterialien auf Basis von Polymeren und Flüssigkristallen mit dichroitischen Farbstoffen

Country Status (5)

Country Link
US (1) US5430563A (de)
EP (1) EP0612827B1 (de)
JP (1) JPH075437A (de)
DE (1) DE69414737T2 (de)
FR (1) FR2702058B1 (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2721316A1 (fr) * 1994-06-21 1995-12-22 Thomson Csf Procédé d'obtention de matériaux composites à base de polymère réticulé et de molécules fluides, comprenant une étape de séchage en phase supercritique.
WO1996013561A1 (en) * 1994-10-31 1996-05-09 Raychem Corporation A method of imbibing a component into a liquid crystal composite and devices including such a composite
EP1094103A1 (de) * 1999-10-19 2001-04-25 Rolic AG Topologisch strukturierte Polymerbeschichtung
WO2001029148A1 (en) * 1999-10-19 2001-04-26 Rolic Ag Topologically structured polymer coating
EP1115809A1 (de) * 1998-09-11 2001-07-18 Reveo, Inc. Strukturell geordnete artikel, herstellungsverfahren und anwendung derselben.

Families Citing this family (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5854664A (en) * 1994-09-26 1998-12-29 Matsushita Electric Industrial Co., Ltd. Liquid crystal display panel and method and device for manufacturing the same
EP0801669B1 (de) * 1995-01-05 2000-12-13 TYCO Electronics Corporation Verfahren zur herstellung eines farbe enthaltenden flüssigkristallkomposits
FR2738831B1 (fr) * 1995-09-19 1997-10-17 Thomson Csf Procede de fabrication de film de materiau a base de polymere
GB2315073B (en) * 1996-07-04 2000-04-19 Patent Gmbh Merck Linear UV polariser
US5818556A (en) * 1996-07-24 1998-10-06 Raychem Corporation Method and apparatus for patterning encapsulated liquid crystal layers
JPH11279558A (ja) * 1998-01-27 1999-10-12 Hitachi Maxell Ltd ポリマー分散型液晶組成物及び該組成物を有する液晶表示素子
JP4268391B2 (ja) * 2002-09-20 2009-05-27 日本放送協会 液晶光変調膜の製造方法
FR2866429B1 (fr) * 2004-02-12 2006-07-21 Thales Sa Capteur chimique tandem hautement selectif et procede de detection utilisant ce capteur
EP1693698A1 (de) * 2005-02-16 2006-08-23 SONY DEUTSCHLAND GmbH Methode zur Herstellung einer PDLC-Zelle, eine mit dieser Methode hergestellte Zelle und Verwendungen einer solchen
CN101373286B (zh) * 2007-08-22 2010-12-08 比亚迪股份有限公司 一种聚合物分散液晶薄膜的制备方法
JP6500286B2 (ja) * 2015-07-02 2019-04-17 エルジー・ケム・リミテッド 偏光素子

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0512397A2 (de) * 1991-05-01 1992-11-11 Canon Kabushiki Kaisha Flüssigkristalleinrichtung sowie diese verwendende Anzeigevorrichtung und Darstellungsverfahren
GB2258318A (en) * 1991-07-12 1993-02-03 Scimat Ltd Liquid crystal materials.

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4354741A (en) * 1979-10-12 1982-10-19 Sumitomo Electric Industries, Ltd. Electrochromic display device
EP0343903A3 (de) * 1988-05-23 1990-10-17 Imperial Chemical Industries Plc Flüssigkristallvorrichtungen
US5372745A (en) * 1990-11-09 1994-12-13 Canon Kabushiki Kaisha Liquid crystal device, display apparatus using same and display method using same
JP3164321B2 (ja) * 1991-03-26 2001-05-08 キヤノン株式会社 液晶素子および表示装置、それらを用いた表示方法

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0512397A2 (de) * 1991-05-01 1992-11-11 Canon Kabushiki Kaisha Flüssigkristalleinrichtung sowie diese verwendende Anzeigevorrichtung und Darstellungsverfahren
GB2258318A (en) * 1991-07-12 1993-02-03 Scimat Ltd Liquid crystal materials.

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2721316A1 (fr) * 1994-06-21 1995-12-22 Thomson Csf Procédé d'obtention de matériaux composites à base de polymère réticulé et de molécules fluides, comprenant une étape de séchage en phase supercritique.
EP0688851A1 (de) * 1994-06-21 1995-12-27 Thomson-Csf Verfahren zur Herstellung von Verbundmaterialien auf Basis von vernetzte Polymeren und flüssige Moleküle in superkritischer Phase eine Trocknungsstufe
US5605727A (en) * 1994-06-21 1997-02-25 Thomson-Csf Method for obtaining composite materials based on cross-linked polymer and fluid molecules, comprising a step of drying in supercritical phase
WO1996013561A1 (en) * 1994-10-31 1996-05-09 Raychem Corporation A method of imbibing a component into a liquid crystal composite and devices including such a composite
US5543944A (en) * 1994-10-31 1996-08-06 Raychem Corporation Method of imbibing a component into a liquid crystal composite
EP1115809A1 (de) * 1998-09-11 2001-07-18 Reveo, Inc. Strukturell geordnete artikel, herstellungsverfahren und anwendung derselben.
EP1115809A4 (de) * 1998-09-11 2007-05-02 Reveo Inc Strukturell geordnete artikel, herstellungsverfahren und anwendung derselben.
EP1094103A1 (de) * 1999-10-19 2001-04-25 Rolic AG Topologisch strukturierte Polymerbeschichtung
WO2001029148A1 (en) * 1999-10-19 2001-04-26 Rolic Ag Topologically structured polymer coating
KR100843639B1 (ko) * 1999-10-19 2008-07-07 롤리크 아게 위상 구조화 중합체 필름 또는 피막의 제조방법, 당해 방법으로부터 제조된 필름 또는 피막, 및 당해 필름 또는 피막을 포함하는 광학 제품
EP2014739A1 (de) * 1999-10-19 2009-01-14 Rolic AG Topologisch strukturierte Polymerbeschichtung
US8906458B2 (en) 1999-10-19 2014-12-09 Rolic Ag Topologically structured polymer coating

Also Published As

Publication number Publication date
FR2702058B1 (fr) 1995-04-07
DE69414737D1 (de) 1999-01-07
DE69414737T2 (de) 1999-04-15
JPH075437A (ja) 1995-01-10
FR2702058A1 (fr) 1994-09-02
US5430563A (en) 1995-07-04
EP0612827B1 (de) 1998-11-25

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